SNR-75M (“Fan Song-E“) radar

(USSR)

Notes: Only a single shipboard example of this radar was ever built, for installation aboard the one Sverdlov class cruiser (Dzerzhinski) converted to fire the SA-N-2 “Guideline” SAM.

It was nearly identical to the land-based “Fan Song” used with the E-mod-4 version of the SA-2 “Guideline” land-based SAM. The major difference was a new power supply to convert shipboard electricity to 400hz 3-phase AC and more sealing against saltwater spray, etc.

The radar was used to track and guide the “Guideline”. It was not an illuminator radar; it merely tracked the inflight missile and sent instructions to it. The “Fan Song-E” consisted of two Lewis-type transceivers, one horizontal and one stood on it’s end, scanning bearing and altitude respectively.

Atop the horizontal Lewis transceivers was a pair of parabolic dishes. One had it’s feed horn set horizontal and scanned bearing, the other had a vertical feed horn for altitude. The function of these dishes was ECCM; in a heavy jamming environment the transmission feed from the Lewis arrays’ waveguides was rerouted to these dishes, while the Lewis arrays still handled the returns and processing.

Finally, the smaller parabolic dish on the side of the array was a radio transmitter which fed course corrections to the missile, it also detonated it as the fuse on the SA-N-2 was radio-controlled.

The radar could only guide one missile at a time however by precisely timing ripple launches, it was possible to have two missiles in the air at once.

The SA-N-2 naval “Guideline” was a failure for various reasons, not all related to this radar; although it was found that this naval version of the radar was less effective than the regular ashore model. Although Dzerzhinski was not formally decommissioned until 1988, the “Fan Song-E” system had likely been deactivated several years before that.